Film registry means for motionpicture projectors



March 9, 1948.

E. BoEcKxNG 2,437,239

FILM REGISTRY MEANS FOR MOTION-PICTURE PROJECTORS Filed April 12, 1945 25 Sheets-Sheet 1 Much 9 948- E. BoEcKlNG 2,437,239

FIL REGISTRY UBAIS FOR MOTION-PICTURE PROJECTORS v Filed April 12, 1945 s sheets-sneet 2 H93 F/'g.2

Y /n vemor BY HIS A TTORNEYS Ewa/d Boeck/'ng E. BOECKING FILM REGISTRY MEANS FOR MOTION-PICTURE PROJECTORS March 9, 1948.

Filed April 12, 1945 3 Sheets-Sheet 3 Ewa/d Boek/nhg 5y H/s A roAwE rs Patented Mar. 9, 1948 FILM REGISTRY MEANS FOR MOTION- ifl PICTURE PBOJECTORS awel-a Boecking, Greet inns, N. Manufacturers Machine & Mount Vernon, N. Y.

York

Y., assiznor to Tool Co., Inc.,

, a corporation of New Application April 12, 1945,'seria1 No. 587,943

(ci. ss-i'z) 3 Claims. l I'his invention relates to lm` registry means y for a motion picture projector. In the usual motion picture projector in which the film advances intermittently, it is quite difdcult for the operator to get the film in proper registry with the light aperture lengthwise of the lm when the film is being iirst threaded in the machine, and he has no convenient way of knowing when the film gets out of registry while the machine is running, except by observing the picture on the screen. The object of the invention is to provide simple and convenient means indicating when the film is in proper registry. It is characteristic of the invention -that the condition of the film with regard to registry determined by means above and separate from the'gate at a xed distance above the intermittent sprocket.

In the drawings:

Figure 1 is a View in side elevation, partly cut away, of a iilm gate and associated parts of a projector embodying one form of my novel registry means, the gate being shown open and the view being taken on the line I-I of Figure 2, looking in the direction of the arrows;

Figure 2 is a. view in vertical section in a plane parallel to the lm through the novel threading registry means of the embodiment shown in Figure 1, taken on the line II of Figure 1;

Figure 3 is a view in longitudinal section of the casing containing the light apertures of my'novel mechanism shown in Figures 1 and 2;

Figure 4 is v a view in elevation from the right side of Figure 2, of the ratchet means controlling the rotation of the casing of Figure 3;

Figure 5 is a plan view, partly disassembled, of the teeth and end of the contact spring shown in Figure 4 for making and breaking current to the light source;

Figure 6 is a view in horizontal section through the core of the casing of Figure 3, showing the teeth and blade for rotating the casing;

Figure '7 is a view in side elevation similar to Figure l of a modified form of registry means combining a visual indicator used when threading up the machine and an electrical indicator for use while the machine is running;

Figure 8 is a view in vertical longitudinal section through the film gate of a preferred form of my registry means in which an electrical indicator uses the lm projecting light as its light source; y

Figure 9 is a view in end elevation of the light aperture of the modification of Figure 8, taken on the line IX-IX of Figure 8;

Figure 10 is a view similar to Figure 8 of a 2 further modified form of my registry means in which a. visual indicator uses the film projecting light as its light source; while v Figure 11 is a view similar to Figure 9 showing the light aperture of the modification shown in Figure 10, taken on the line XI-XI of Fig. ure 10.

In a commercial motion picture projector in which the lm advances intermittently, it is a somewhat complicated process to thread up the machine-at the beginning of the lm. In threading up the machine heretofore, the operator had to hold the film at the light aperture and try to peek into the iilm gate to see that it was in registry. Then, while holding the lm stationary atthat point. he had to thread it onto the intermittent drive sprocket and shut the film gate without catching his lingers which Were still holding the nlm in the gate. Again, after the machine had been properly started, there was no convenient way by which examination of the machine Would tell the operator Whether the lm had stayed in registry or been thrown out of registry by the lm jumping or by improper patching of the iilm.

I have invented a construction by which the operator has indicating means which will signal when the lm is not in proper registry. These means may be visual, audible or electrical.

I shall first describe the form in which the registry condition at the light aperture of the machine is signalled visually above the film gate. As shown in Fig. 1, .there is the usual lm gate l0 movably mounted on bar means i I and carrying with it lenses I2 shown at the right of-the figure. The lm gate has the usual projection aperture corresponding to the light aperture I6 hereinafter referred to. The source of light, of course, is to the lef-t of the lenses I2 and the screen is some distance to the right, as shown in this gure. Movement of the :lilm gate I0 and its mount l I is controlled by mechanism I3 which need not be described here, it being sufficient to point out that the purpose of making the lm gate l0 movable toward and away from the film is to facilitate threading up of the machine. I have shown the film gate in its retracted position. 'Ihe film il lies between the lm gate, on the one hand, and the pressure shoes I5 and light aperture i6, on the other. It will be noted that the iilm gate presents a' vertically convex surface to the film and that the pressure shoes i5 present a surface which is concave to match the concavity ofthe film gate. This is for the purpose of holding the lm in proper position for projection, as described in my co-pending application Serial No. 567,967, filed December 13, 1944. The usual intermittent driving sprocket wheel Il with its pad roller I8 pivotally mounted about the center I9 is shown below the film gate. Below that sprocket wheel I'I is shown the lower pad roller in its open position which, when the machine is running, transforms the intermittent movement of the lxn back to continuous movement. Above the lm gate, and separate therefrom, is the corresponding upper pad roller 2I-also shown in open positionwhich feeds the illm forward continuously. It should be noted that these two rollers being shown in open position in Fig. 1, the slack loops adjacent them do not appear in their running condition. The purpose in having these rollers shown in their open position is to illustrate more clearly the simplicity of getting the film into registry by use of the novel means which I have invented and will now describe.

Above the usual plate 22 which carries the pressure shoes I5, and on the opposite side of the film I4 from the lm gate I0, is a hold-back roller 23 which is the casing of my registry means. To hold the film in contact with this casing while the machine is running, there is a lateral guide roller 24 mounted on -the film gate by means of a horizontal shaft 25, and a double guiding yoke 26 adapted to overlie the lines of the sprocket holes on the two sides of the film I4. The upper end of this yoke is pressed against the film by adjustable spring means 2l in a manner similar to the spring 23 and screw 25 of my copending application Serial No. 560,654, filed October 27, 1944, now Patent Number 2,429,918, issued November 28, 1947. The casing 23 contains around its periphery one or more apertures 28, there being ve such apertures indicated in Fig. 1 and each aperture being the exact size of a picture on the film. The'diameter of the casing is so calculated that the amount of metal between any two openings is equal to the space or bar 29 between two adjacent pictures 3U (see Fig. 2) on the lm so that the circumferential distance around the roller from say the upper edge of one opening 28 to the upper edge of the next opening is equal to the length of a lm frame. As shown in Fig. 1, each rib 3| between two openings 28 in the casing is bevelled on the sides so as to maintain a space of uniform width for the passage of light from the center of the casing. This casing is so located and of such a length that it extends across the full width of the film and on the side on which it is mounted extends for some distance beyond the film, as can be seen in Fig. 2. The casing is hollow and the hollow space 32 opposite the film is large enough to contain an electric light bulb 33 whose base is screwed into a screw shell 34 with a, center screw contact 35 constituting the socket inside the casing.- It will be seen that by providing suitable electric current for the light bulb when the film is held in contact with the periphery of this roller or casing, the relation of the nearest picture on the film to the aperture 28 facing the roller 24 can be ascertained at a glance.

The casing is mounted separately from the lm gate and above it. It does not move when the lm gate is retracted for threading up the machine. The casing is in such a position that when the iilm gate is open the film passing over the casing goes in a straight line to the intermittent sprocket Il without touching the curved gate at all. The iilm does not register properly with 4 the light aperture I6 under these conditions. The spacing of the casing is from the intermittent sprocket and is such that when the film is meshed with the teeth of the intermittent sprocket the lm will be in register with one of the openings 28 of the casing. In this way the adjustment of the film at the light aperture is determined across the -light aperture I6 although the iilm is not yet in proper register to check at the aper.-

ture itself. I find that the diierence in length of path of the portion of iilm between the intermittent sprocket and my casing due to the curvature of the film gate is so slight that it does not interfere with the casing being used as a check for the meshing with the proper teeth on the intermittent sprocket, both when the gate is open and when it is closed. The registry of the lm with the light aperture is accurate, of course.

I will now describe the operation of threading up the projector when using my novel registry means of Figs. 1 to 6. Assuming that the upper roller 2|, lower roller 20 and intermittent driving sprocket wheel I'I are open, an adequate length of film is taken off the,reel, the lm led around the upper roller 2l over the casing 23 of my film registry means between the gate and pressure shoes I5, and through the sprocket wheel I1 and the lower roller 20.* The sprocket wheel I'I, which has its pad roller I8 close against'lt, thus holds the illm in a denite position as far as concerns registry with the light aperture. It will be observed that with the exception of this one sprocket wheel Il, the lm can still be moved through any of the other elements with which it has been put in contact. The operator then grasps the iilm with his finger at the point marked with the arrow 36 in Fig. 1 and the lm is held down around a portion of the periphery of the casing 23. Assuming that the bulb 33 has been turned on, the operator can see whether the iilm is in registry. If it is not, he cany move the film to another sprocket hole on the wheel Il or can make adjustment by the usual nlm framing device which is found on practically all modern machines to take up slight erors in adjustment when the machine is running. If desired, the operator can check with the registering means before putting the film on the teeth of the intermittent driving sprocket wheel. When the picture opposite the opening 28 in the casing is in registry with the opening, the operator is assured that the picture opposite the light aperture in the lm gate will be in registry when the gate is closed and the threading of the machine can be completed. The fihn gate is then closed and the proper size of slack loops formed between the threading loops and the upper sprocket wheel or roller 2l, and then the necessary slack loop between the intermittent sprocket wheel Il and the continuous lower roller 20 obtained, and the machine is ready to be run.

The manner in which these slack loops can be obtained by the use of the particular upper and lower sprocket rollers 20, 2l is not part of the present invention and therefore need not be described here. I will now turn to a description of the features of my invention which center about the turning of the casing to bring up difierent apertures.

I provide these apertures for two purposes: first, as a convenient means of turning the light on and oi and, secondly, to insure that the wear of the film on the casing because of its holdback function is distributed evenly around the casing. To this end the casing 23 is a roller adapted to turn about the longitudinal or horizontal axis on which it is mounted, in a step-bystep manner. This movement, Vshown in the drawings, is such that at each two steps which the roller turns, the next aperture 28 is facing the roller 24. In other words, each two steps that the roller turns correspond to a peripheral distan-ce of one film frame on the roller. This turning is obtained conveniently by means oi a knob 31 se't in the end of the roller 23, as shown at the left of Fig. 2. This knob 31 can be removed from the recess 55 in the end of the casing to give access to the bulb. The knob is split longitudinally and contains a wedging-screw 59 to wedge the knob in place by expansion against an internal shoulder 58 (Fig. 2).

The control of this turning of the roller and turning on and oiI of the electric current centers around a light-contacting ratchet gear 38 and a positioning or insulating ratchet gear 39 and their companion contact spring 40 and hold-back arm 4|, shown in Figs. 2, 5 and 6. These ratchet gears 38, 39 are mounted on the other end of the casing from the knob 31. As shown in the drawings, the insulating ratchet gear 39 is between the casing and the electrical ratchet gear 38.

I will now describe the manner in which the hold-back roller is mounted. The roller is attached to the frame of the machine by means of a stationary casting or bracket 42 which is clamped around the small or supporting end by a clamp 43 and screw 44. In order that this mounting may be adjustable with relation to the nlm, an adjustment tube 45 is interposed between the clamp 43 and the outside of the sleeve 46 of the casing. To hold the sleeve 46, adjustment tube 45 and clamp 43 against lateral separation, one end of the adjustment tube rests against the adjacent. enlargement or shoulder 41 on the casing which occurs where the casing is enlarged to contact the film. The other end of the adjustment tube abuts against a spring washer 48 taking into a notch 49 in the free end of the sleeve of the casing. This spring washer 48 has an external circumference greater than the internal diameter of the clamp 43 so that even if the screw 44 is loosened the casing cannot come out .of the clamp until the spring washer is removed.

Relative longitudinal movement between the adjustment tube and the sleeve of the roller is also impossible until the washer is removed.

The screw shell 34 in which the-electric light bulb 33 is placed is mounted at one end o'f a core 50 which fills the center of the sleeve 46 of the casing except for a recess at the aperture end for the screw shell. This core 50 is held against removal from the sleeve by a screw passing through the sleeve from the outside but not through the adjustment tube 45 (see Figs. 2 and 3). The core is made of insulating material such as formica and the insulating or advancing ratchet gear 39 is integral therewith on the outer end of it. It is larger in 4diameter than the balance of the sleeve but n0 portion of it projects radially outward into the path of the clamp. The electrical contact ratchet gear 38 is mounted outside the insulating ratchet gear 39 and is held at an axially central point by the center contact screw 35 for the light bulb. This screw extends through from the screw shell end of the core to the outside ,surface of the electrical contact gear 38. To permit an exact adjustment of this longitudinal contact circumferentially, a small set screw 53 taking into a depression in the insulating gear .then be turned to bring an opening (not shown) opposite the screw 5| in the sleeve 46, thus freeing the core 50 to be withdrawn from the free end of the sleeve.

I will now describe more fully the ratchets and electrical circuits cooperating with the ratchet gears 38 and 39 to provide accurate stopping of the light apertures in the casing and to provide the make-and-break of the electric current for the light source in the casing. I provide the insulating stop or hold-back arm or blade 4| of comparatively rigid material flxedly depending lfrom a pin 52 pivotaliy mounted above the two ratchet gears 38, 39 on the stationary casting 42. This pin is insulated from the casting by washers 56 and sleeve 51 so that there is no electrical connection between the casting and frame of the machine and the clamp screw, onk the one hand, and the means mounting this stop blade 4|, on the other hand.v 'I'his blade may be comparatively rigid and made of any phenolic or other desired compound, provided the same has a modcrate amount of resilience to permit it to be drawn over the teeth of the insulating ratchet gear 39 as the latter is turned, and will fall in behind each tooth as it passes. It will be -obvious from the drawings that the direction of rotation of these ratchet gears 38, 39 is opposite to that of the direction of movement of the lm -so that when the operator, by turning the knob 31, causes one of the teeth on the gears to pass the stop blade 4|, the contact with the iilm will immediately press the vertical back face of the tooth against the end of the stop blade, thus accurately positioning a light aperture 28 with relation to the distance to the light aperture I6 in the film gate and the dimensions of the frames in the lm. I prefer to mount the electrical contact spring for providing the light on the same pin which-carries the insulating stop blade 4| and therefore I have shown in the drawings a Contact spring 40 screwed to the sleeve by the same screw 54 that holds the stop blade on the pin 52. This contact blade is somewhat longer than the stop blade 4| and, being on the side of the stop blade away from the axis of rotation of the two ratchet gears, although it is opposite both ratchet gears like the insulating blade 4|, it is limited and controlled by the stop blade as follows:

It may be observed that While the insulating and electrical ratchet gears 39, 38 have the same number of teeth and the same radial diameter for the teeth, the teeth on any one gear are apart a distance equal to two teeth and the two gears are set so that looked at from the end of the hold-back roller, the teeth are in staggered position (see Fig. 4). The stop blade 4| being the vwidth of and lying opposite both ratchet gears, it

engages alternately behind a tooth on the insulating gear and a tooth on the electrical gear as the hold-back roller is rotated. As shown, there Vare ve teeth on each ratchet gear and live light apertures in the casing. Since the teeth are set casing and associated in the equally spaced staggered relation described. it follows that in one rotation the casing is stopped ten times. On every other Vmovement forward it will be seen that the tooth which the spring 40 contacts or lies on top of will be a. tooth on the electrical ratchet gear 38. This is the position shown in Fig. 4. In this position the blade 40 is in contact with a tooth on the electrical ratchet wheel 38 but when the ratchet wheels are advanced one tooth further, the blade will be out of contact with the teeth on the electrical ratchet wheel and merely lying on top of the insulating gear 39. Thus, as the casing is turned, the electrical circuit is alternately made and broken. It will be seen that the light source will be turned on ve times in each complete rotation of the casing. The parts are so setl that this occurs when the casing is in registry position with the lm while the latter is being projected, as above mentioned, and that when the current is off, the casing is advanced half way to registry position for the next aperture. The electric circuit thus completed by the spring contact 40 is composed of the screw 54 holding the contact on the sleeve, the screw 52 holding the blades 40 and 4l on the casting 42, a wire 60 connected to the other end of the screw 52 on the opposite side of the casting, a source of current which may be say from six to twenty-live volts, and a ground wire 6l attached to the casting which transmits the current through the clamp to the screw shell in any well-known manner.

It will be noted that while the embodiment shown in Figs. 1-6 moves the handling and registry of the film to a place where the operator can thread the machine without awkwardness or danger to his fingers, it also provides ay visual check on the registry of the film while the machine is running. This visual signalling of the accuracy of the registry of the film may be obtained not only by looking directly at the lm as it passes over the slot or aperture in the holdback roller, but if desired such image can be reflected by a mirror or other means to any desired position or dimension. When using the roller 23 of Fig. 1 for a visu-al indication of registry while the machine is running, the operator looks at the rib 3| between the openings 28 which are facing upwardly and the lower guide roller (24) opening and yoke 26 for the casing. The operator can see this rib over the top of the roller and yoke. By watching the rib-and more particularly its upper edge-the operator can see if the space or bar 29 on the film is in registry with vthe rib of the casing. (The approximate running position of the film can be seen in Fig. 7.)

If it is desired to obtain some indication other than visual of the condition of the iilm while the machine is running, an electrical impulse or an audible signal can be obtained (Fig. '7). The casing 63 in this embodiment has only two openings and does not revolve. One of these is an opening 64 facing upwardly which is the same size as one of the openings 28 in the embodiment of Figs. l to 6, and this is used to obtain registry when threading up the machine. When detecting faulty registry while the machine is running, a small slot 65 facing almost horizontally just under the pad roller 24 is used. The slot is slightly less than the size of the space or bar 29 between two pictures on the lm and is spaced a multiple of the film frame above the corresponding bar just above the picture in the light aperture. It will be seen that while the frame at the light aperture is being projected, a bar 29 of the illm is over the slot 65. This bar, of course. covers the slot, cutting oi the light from the light source 61 inside the casing. If the film is out of registry, obviously light will escape and can be translated into electrical impulses by a selenium cell 81 in a jacket 1l on the frame of the machine. The wires 69 carrying the current for the selenium cell can transmit the electrical indications to any desired electrical equipment, whether it be operating or signalling equipment. Thus, for example, the electrical impulses can be used to operate automatic lrn framing mechanism.

The light source 61 in the casing 63 is shown as-a neon or gaseous discharge light. It will be obvious that unless the light is extinguished while the lm is advancing from one position to the next, the selenium cell 68 will be operated when it should be idle. Stroboscopic control of the circuit 66 supplying alternating current to the light can be used to take care of this, or a switch in the circuit can be connected to the light shutter of the projector. However, I have indicated 'another alternative in Fig. 7 where there is shown a half-wave rectier 10. This gives current which is interrupted sixty times per second. Each pulse of current takes place in one one-hundred-twen-- tieth of'al second and that is equal to the time it takes for the lm to be advanced from one frame to the next.

In Figs. 8, 9, 10 and l1 I have shown two simplied embodiments of my invention in which the light source for my indicator is the arc light which projects the picture on the screen.

In Fig. 8 there is a photo-,cell l2 similar to the photo-cell 6B in Fig. 7 except that it is located down in the lm gate with its opening 13 directed toward the bar 29 just above the picture which at -that moment is in the light aperture 75. The slot to direct the source of light against the bar to detect any irregularities in the registry is an opening 'i4 in the aperture plate just above the regular light aperture (Figs. 8 and 9). This slot may be formed with tapered walls as shown, so as to take in only excess which normally would not go through the regular light aperture. By this I refer to the light cut oi when the aperture 'i5 or 80 cuts the beam from a circle to an oblong. When the registry of the film is bad the light rays going through the slot lli hit a reflector i6 which deects the' light into the slot i3 and to the selenium, i. e., photoelectric, cell 12. As shown in the drawings, the light beam 11 coming from the left of the figure is interrupted by the shutter 78 so that the beam used to indicate the registry faults will not reach the cell when the lm is moving. The cell ls Wired in the same manner as the one in Fig. 7. Of course, it can be used to produce visible, audible or electric current indications as desired. I prefer to use the picture projecting light in carrying out my invention, and the construction shown in. Figs. 8 and 9 is the preferred form of the two arc light embodiments.

In Figs. l0 and 11 is shown an embodiment in which the light which projects the film on the screen also operates a visible form of registry indicator. As in Figs. 8 and 9, a slot 'i9 is formed in one edge of the light aperture Sil-this time in the lower edge. As can be seen in Fig. 1l, the slot is tapered down to the same size as the bar 29 between two pictures on the lm. The slot takes excess light and not useful light which otherwise would go in the main light aperture 9D. 0n the 111m gate opposite this slot 19, instead of a passage leading to a photo-electric cell, there is a reilector 82. This turns any light beams coming through the slot 19 and the iilm horizontally at right angles. These beams of light strike on thel usual glass `door 8| on the side of the projector opposite the film gate. At the point where such rays would strike a red dot, a red line or other symbol can be painted. When this is illuminated the operator can see it almost anywhere in the projection booth and will know the iilrn is out oi registry.

Et will be noted that either of the two defined portions of the film, namely, the picture or the bar between pictures, on the registry of the picture in the light aperture. If it is desired that the operator see the actual registry condition of the iilm, then a direct visual check is obtained from a picture portion of the iilm (Figs. 1 to 6). When it is not considered necessary that the operator see the actual picture, then the bar between pictures is used either to give a visual indication as in Figs. and 1l or to give indirect indications such as are obtainable from the photo-electric cell (Figs. 7 to 9).

It will be seen that according to my invention the indicationsof iilm registry are taken from points above or below the picture being projected and by means oi' a light source can give vany desired type of indication.

What I claim is:

l.. An intermittent motion picture projector having a retractable curved iilm gate with the usual projection aperture, and an intermittent sprocket below the iilm gate, in combination with a hold-back roller above and mounted separately from the gate a fixed distance above the sprocket, said roller having a casing with one or more slots therethrough over which the lm can pass in a straight line to the sprocket without touching the gate when the gate is retracted, a' light source inside said casing to project light through said openings, the distance from the casing to the sprocket being such when the gate is retracted that the iilm is in register with one o1' the openmay be used to give a check ille of this patent:

'UNITED STATES PATENTS Number Name Date '2,132,003 Holst Oct. 4, 1938 1,348,566 Jenkins Aug. 3, i920v 1,433,475 Porter Oct. 24, 1922 1,486,226 Capstaif Mar. l, 1924 1,956,419 Flinker Apr. 24, 1934 1,491,017 Malm Apr. 22, 1924 40 2,192,987 Runge Mar. 12, 1940 FOREIGN PATENTS Number Country Date 467,161 Germany Oct. 19, 1928 367,388 Germany Jan. 20, 1923 ings when the iilm is properly meshed with the teeth of the sprocket, the aperture in the curved illm gate being solocated that it is in register with the iilm when the gate is closed.

2. A motion picture projector in accordance with claim 1 in which said casing has a plurality of apertures to project an image of light approximately the size of a picture frame against the iilm to be threaded, and means for extinguishing the light source adapted to cause rotary successive steps of said casing of hali' a lm frame in a direction opposite to the iilm travel so that the light. source is turned on when film is threadecl and may be turned oil? and on when iilm is moving.

3. A motion picture projector in accordance with claim l in which there are means associated with the casing adapted to cause step-by-step turnings of the casing and thereby successively turn the light source ofi and the light source is on being ones in which the openings are identical with a picture frame, whereby a visual check on the film is obtained and the wear of the casing due to iilm friction is kept even.

JWALD BOECKING.

REFERENCES CITED The following references are of record in the on, the steps where 

